eobebtson



(No' Model.)

J. H. ROBERTSON.

ELEeTEIe TELEPHONE.

Patented May 1,1883.

W'Zizssea wuha hr, wan-"m. n. a

UNITED STATES PATENT OFFICE.

JAMES H. ROBERTSON, OF BROOKLYN, NEW YORK.

ELECTRIC TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 276,631, dated May 1, 1883.

Application filed August 17, 1882.

phones, of which the following is a specification, reference being had to the accompanying drawings, forming part of the same.

Figure 1 is a face view of an apparatus con-- taining my improvement, and Fig. 2 is an edge view of the same.

My invention relates to the supporting and retaining in its place in a telephone of the vibrative diaphragm, so as to secure the utmost possible freedom of vibration; and it consists of the devices hereinafter described and claimed.

The drawings show my invention as applied to a telephone-transmitter. It may also be. applied to the diaphragm of a receiver.

A is the diaphragm. It is represented as secured to a door, B, of a case intended to inclose the apparatus. The mouth-piece (not shown) communicates with the diaphragm through an aperture (also not shown) in the door.

a is one of the electrodes, fixed to the center of the diaphragm, and bis the other electrode, suspended from the bracket O by the wires 0 c, as shown in Fig. 1.

d d are the circuit-wires, the former connected to the bracket 0 and the latter to the diaphragm A, thus establishing the circuit over the said wires and through the bracket 0, the wires 0 c, the diaphragm A, and the electrodes a and b. The wire (1 may connect directly with the electrode a.

The method described and shown of suspending the electrode I), I regard as new; but I do not intend to claim it in this specification. I reserve it for a separate patent for which I purpose making application. Nor do I here (No model.)

limit myself to the particular device described for arranging and holding the electrode 1) in contact with the electrode a. Anyother known device for the purpose may be employed.

My improvement relates, as before stated, to the devices employed for supporting and retaining in place in the telephone the diaphragm. The method heretofore employed has been to support the diaphragm by its rim on a rigid or a yielding or elastic substance, and in some suitable way secure it on such support. With this arrangement the entire perimeter of the diaphragm is supported by and in contact with the supporting substance, which necessarily suppresses or interferes somewhat with the vibrations ofthc diaphragm in response to the impulses from the soundwaves. I have found that by supporting the diaphragm, near its perimeter, at several separate points, its vibratory action is improved. The circles a a a in dotted lines in Fig.1 show where I place the supports, and at a cf, Fig. 2, are shown two of the supports. These are made of rubber in the form of small disks or short studs attached by cement preferably to the door B. Preferably three of these supports are used, as that is the smallest number that will properly support the diaphragm. They may be placed about equidistant from each other just within the perimeter of the diaphragm, which is attached to them by any suitable means, preferably cement.

hat I claim as my invention, and desire to secure by Letters Patent, is-

The diaphragm A, supported and secured in its place in a telephone at separate points only by means of the rubber disks or studs (1 a a as and for the purpose described.

JAMES H. ROBERTSON.

In presence of-- P. B. VERMILYA, A. G. N. VERMILYA. 

